Valve-Sparing Aortic Root Replacement

Abstract

In patients with a properly functioning aortic valve who have a root aneurysm, it is possible—and in the present era, popular—to spare the valve. We use this procedure predominantly in young patients, especially young women of childbearing age, in whom it is helpful to avoid coumadin. Others use it very widely.

Questions and Answers

[Some of the answers in the first section are provided by Dr. Duke Cameron (DC) of the Massachusetts General Hospital, who has done pioneering work in this field, including instructing worldwide regarding the optimal conduct of these operations.]

• BAZ: How deep do we really need to go in mobilizing the aortic root? Why?

• DC: For the reimplantation procedure, mobilization ideally should be down to and below the level of the annulus in all sinuses. This is because annular stabilization can only be assured if the prosthetic graft encircles the entire annulus. This is usually not problematic in the left and non-coronary sinuses but can be challenging in the right sinus. For the remodeling procedure, the graft sits atop the annulus rather than around it, so full mobilization is not as critical, but a more secure suture line is achieved after full mobilization, even if a stabilizing suture or external band is added for annular stabilization.

• BAZ: How does one avoid entering the RV in mobilizing the aortic root?

• DC: Entering the RV infundibulum is avoided by careful dissection between the aortic wall and RV muscle, but may still happen when the RV wall is thin or when the lower part of right sinus is “muscularized” similar to that seen in porcine roots.

• BAZ: How does one repair an entry into the RV, should it occur?

• DC: An important step after mobilizing the root is to occlude the venous line of the cardiopulmonary bypass circuit, fill the right heart, and look for holes in the RV. Most can be repaired directly with horizontal mattress sutures with pledgets. Occasionally, sutures passed from within the right sinus through the muscle are necessary. The key is to identify and repair the defects before the root graft is lowered and secured, and especially before the right coronary artery is implanted.

• BAZ: How does one treat bleeding coming from the bottom of the Valsalva graft after the operation is completed? We recognize that the hemostatic suture line is the root reimplantation line, but can we put stitches in the bottom of the graft? Will those help at all? Do we need to reopen the graft and resecure the internal suture line?

• DC: Minor bleeding is common and can be treated by plicating the base of the graft below each of the commissures, creating a tighter constriction of the graft around the sub-annular area. Significant bleeding should prompt aortic reclamping, rearrest of the heart, and transverse division of the graft to inspect the internal suture line and repair gaps or folds in the sinus remnant, which should lie flat against the graft.

• BAZ: How much aortic insufficiency (AI) can we accept after completion of the operation? What are your guidelines?

• DC: Any AI more than mild is probably not acceptable, but it also depends on the direction of the regurgitant jet and the mechanism of AR. Thickened nodes of Arantius may prevent central coaptation of the leaflets and lead to mild AR. If the AR jet is central and not-eccentric, this AI will probably not progress and is therefore acceptable. However, an eccentric jet due to leaflet prolapse will worsen with time and should be addressed, usually by midleaflet plication. Small commissure jets are probably benign.

• BAZ: If we have severe AI, and we decide to replace the valve, how should we do this? Should we save the root reimplantation, resect the leaflets, and implant the valve within the construct? Or, remove the construct and perform an ordinary aortic root replacement?

• DC: In this scenario, whether a simple valve replacement is possible or whether the root must be re-replaced will depend on fitting an adequate size valve prosthesis within the prosthetic graft. If a Valsalva graft has been used originally, a larger prosthesis can be placed higher in the sinus segment, as long there is good clearance below the coronary artery implants. If the problem is uncorrectable bleeding, the root should be re-replaced.

• BAZ: Why not do a valve-sparing procedure in everyone?

• JAE: Dr. Coselli’s study (of the best centers in the world) showed a significant early incidence of aortic insufficiency after valve-sparing procedures in Marfan patients. For middle-age or elderly individuals, I personally prefer the near certitude that a mechanical or biological valve (respectively) will see the patient safely to the end of his life, without concern for residual recurrent aortic insufficiency or need for future reoperation. Our reoperation rate is near zero [4]. I have spent 39 years operating in one very same hospital. My patients follow with me lifelong. My aim is, if I operate through a sternotomy, for them never to need an operation in that territory again. This is almost always achieved by the approach described above.

If the PROACTXa trial is favorable, the elimination of coumadin for mechanical valves will change the entire landscape. However, I hasten to point out that experienced aortic surgeons differ greatly in their perspectives regarding the application of the valve-sparing procedure. Some are extremely aggressive in this regard—based on their clinical experience.